Radisys EPC Index (EXM Format)

EMC - Embedded Modular Computer
EPC - Embedded Personal Computer
EXM - EXpansion Module

Inserting an EPC into an EXM Carrier  
Note: Make sure that power to your system is off. The EPC-23 is not designed to be inserted or removed from a live system.

Notice: Use of any of the files or information on this page is AT YOUR OWN RISK. If you want a guarantee on this stuff, seek out any repair / service company that supports EXM / EPC devices.

If you have any files or experience with these devices, please reach to Louis Ohland.

EPC-2x Type Index 

Type 1 - EPC-21 / -22 Based on 386SL
Type 2 - EPC-23 Based on 486SL
Type 3 - EPC-24 / -25 / -26 Based on 486 Enhanced (3.3v SIMM)
Type 4 - EPC-26A / -27 Based on 486 Enhanced, Pico Power chipset (3.3v SIMM)

EPC "Types"

I know Radisys never grouped their EPC-2x into "Types", akin to IBM's processor complexes. But if you look at the Radisys documentation, the -21/-22 share the same archive, the -23 is alone, the -24/-26 share the same archive, and the -26A/-27 share the same archive.

EPC-5/-7/-8 vs EPC-2x

VME / VXI Carrier
EMC Chassis

VME / VXI system EPCs already have a system board as part of their chassis. They CANNOT accept an EPC-2x module and function. The EXM bus does not support ISA busmasters. VME / VXI can host many of the EXM modules. Check the EXM module's documentation.

EMC based systems accept any EXM size format EPC-2x CPU module. The EXM bus does not support ISA busmasters.

Note: If you want to impress me, get a EXM-12 Prototype module and make a busmastering support circuit.

The Mysterious EPC-25
   There is a gap in the EPC numbering convention, -25. It may be the way it is, but I have read ONE press release that said

i486 options for embedded control HERE  
This article was posted on 06/01/1994
Board comes with three 486 options for embedded control: 25-MHz 486SX, 33-MHz
486DX, and 50-MHz 486DX2; all come with up to 16 MBs of RAM, 128 KB of
battery-backed SRAM, and 2 MB of flash memory; a serial port and a keyboard
port are included along with a PC-compatible BIOS; available now.

From $785

RadiSys Corp.
Beaverton, OR
Steve Verleye 503-646-1800

Radisys ECP Processor Module Ports (EXM Format) 
Warning! Some EPC modules are incompatible with other modules or carriers. Please read the documentation from Radisys. Do NOT assume the EPC format module is compatible in your application!

No BIOS flash images to be found for any EPC-2x

EPC-2x CPU Module Ports
Although this is an EPC-22, all EPC-2x CPU modules have the same ports.

RESET - causes EPC to perform hardware reset. The system will run POST and reboot the operating system

RUN - LED lit during memory access. It comes on at power-up and stays lit while system is running. It normally flickers during power-up. If CPU halts (or hangs) , the LED will go out.

COM2 - RJ45

COM1 - DB-9  DTE serial port

KB - 6-pin DIN AT only? Does not accept PS/2 keyboards?

Battery - Panasonic BR2330 or Rayovac BR2335

COM1 Serial Port (DB-9)

 Pin  Signal  Pin  Signal
1  DCD 6  DSR
2  RxD 7  RTS
3  TxD 8  CTS
4  DTR 9  Ring indicator
5  Ground    

COM2 Serial Port (RJ45)

 RJ45  Signal  DB25
1  Shield 1
2  CTS 4
3  TxD 3
4  DTR 8
5  RxD 2
6  DCD 20
7  Ground 7
8  RTS 5

Oh, ho... So there was an RJ45 to DB-25 cable. RJ45 to DB-9 should be possible.

EPC-2x Keyboard Port

 Pin  Signal  Pin  Signal
1  Data 4  +5V
2  not used 5  Clock
3  Ground 6  not used

Note: Though this is a mini-DIN 6 pin socket, it might not support PS/2 keyboards.

So why the fuss over AT keyboard? Just to ensure any old Radisys keyboards can be used with an AT to PS/2 adapter?

Battery - Panasonic BR2330 or Rayovac BR2335. All CMOS values will be lost when you pull the battery.

Substituting a CR2032

Well. A 2032 coin cell will work, it is only 20mm in diameter. The two listed batteries are 30mm and 35mm in height.

Floppy Types Supported
The EPC-2x support 360K, 720K, 1.2 MB, 1.44MB, and 2.88 MB. BUT... If you look at the EMC-FDM, it appears to have a max 500Kbit/s transfer rate, which suggests to me that it tops out at 1.44MB floppies.

So if you want 2.88MB floppy support, you might have to choose an EXM module with an external floppy header.

Configuring an EXM Module  
My guess is Radisys could not emulate IBM's autoconfiguration, due to patents. The EXM bus has a signal, EXMID, that sure resembles POSID. But for reasons known only to God, you have to manually calculate and populate three hexadecimal byte-pairs, ID, OB1, OB2.

Finding ID, OB1 and OB2 Values 
Look in the Radisys documentation, usually Chapter 2.

Example: Configure EMC-FDM (COM, LPT, Floppy)

The EMC-FDM occupies the two open slots on the far right of the chassis.

Bits to Hexadecimal 
You will notice that the OBx documentation lists bit values of 1 or 0, and there are 8 digits (bits). Again, look at the Radisys documentation for that module, and specifically in Chapter 2. Take your time, because the tech writing is indifferent...

The leftmost bit (bit 7) is the highest value (Most Significant Bit). Bits 7-4 are the hexadecimal left byte, bits 3-0 are the hexadecimal right byte.

I use the format of 0  0  0  0  - 0  0  0  0 because it is easier to distinguish the bits for the left Hexadecimal byte from the bits for the right Hexadecimal byte.

Decimal - Binary - Hexadecimal Chart 
0 0000 0
1 0001 1
2 0010 2
3 0011 3
4 0100 4
5 0101 5
6 0110 6
7 0111 7
8 1000 8
9 1001 9
10 1010 A
11 1011 B
12 1100 C
13 1101 D
14 1110 E
15 1111 F

Note: Yes, there are sixteen Hexadecimal values (0-F), remember that 0 (zero) is one of them. So Hexadecimal goes up to 15 Decimal.

Award EXM Setup  (EPC -21/22/23)

Phoenix EXM Setup   (EPC -24/25/26/26A/27)

ID Byte is a hard-wired ID value. The EMC-FDM should be set to 7C
OB1/OB2 are two bytes of option information [Option Byte or OB].

Note: slots without EXM module have ID of FF and OB1/OB2 of   00  00.

Calculate OB1 and OB2

OB1 Bytes

(bit 7) (bit 6) (bit 5) (bit 4, 3) (bits 2,1) (bit 0)
Parallel Port I/O Enable Parallel Port Enable Printer Port Select COM Port Interrupt COM Port Base Address Card Enable
1=Enable output 0=Enable input 1=Enable 0=Disable 1=378, IRQ7 0=278, IRQ5 00=Disabled 01=IRQ3 10=IRQ4 11=IRQ9(2) 00=Disabled 01=2F8h 10=3E8h 11=2E8h 1=Enable card 0=Disable card, IRQs

Disable LPT and COM, but enable card (floppy support)
0  0  0  0 - 0  0  0  1 binary, becomes 0 1 in Hex.

Enable LPT for printing [output], disable COM, enable card.  
1  1  1  0 - 0  0  0  1 binary, becomes E 1 in Hex.

Note: Remember the EPC has >TWO< COM ports, so you'd better be cautious on enabling the EMC-FDM's COM port.

Note: In general, attaching a mouse to a serial port only works on COM1 or COM2.

OB2 Bytes

(Bits 7-2) (bit 1) (bit 0)
Masked Reserved Floppy drive enable
1 1 1 1 1 1 1 = default 1 = Enable floppy drive, DRQ and IRQ, 0 = Disable floppy drive

Simple, bits 7-2 are masked to 1, bit 1 is reserved, and bit 0 enables the floppy drive.

Enable Floppy Drive 
1  1  1  1 - 1  1  1  1 binary, becomes F F in Hex.

Note: This is OB2, not ID. An OBx value of FF does NOT mean empty.

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Louis Ohland, Peter Wendt, William Walsh, Kevin Bowling, Jim Shorney, Tim Clarke, David Beem, Tatsuo Sunagawa, Tomáš Slavotínek, and many others.

Ardent Tool of Capitalism - MAD Edition! is maintained by Tomáš Slavotínek.
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